of westminster



F. G. L. JOHNSON.

SHELL FUSE.

APPLICATION m zn NOV. n. 1918.

Patented Nov. 18,1919 7 UNITED STATES PATENT OFFICE.

FREDERICK GEOFFREY LEES JOHNSON, OF WESTMINSTER, LONDON, ENGLAND,ASSIGNOR TO VICKERS LIMITED, OF WESTMINSTER, LONDON, ENGLAND.

sHELL-EusE.

To all whom it may concern:

Be it known that I, FREDERICK GEOFFREY LEEs JOHNSON, a subject of theKing of Great Britain, residing at Vickers House, Broadway, Westminster,in the county of London, England, have invented certain new and usefulImprovements in or Relating to Shell-Fuses, of'which the following is aspecification.

This invention relates to shell fuses of the time type and has for itschief object to provide a fuse in which the timing can be effected withaccuracy, the slow burning operated by the set back of an inertia memberwhich at or toward the end of the cutting operation fires a percussioncap and ignites the end of the fuse, 1gn1t1on therefore taking placeonly after cuttlng.

In the preferred arrangement, the cutter simultaneously severs two fusecolumns or lead tubes,-which may be superposed one upon the other or maybe arranged in spiral form lying side by side, 1n whlch latter case thecutter must be adjusted in settlng the fuse to move upon a spiral path.For this purpose the cutter may be mounted to slide upon a radial pinand may be guided by a spiral channel or a wall in a spirally arrangedholder for the fuse. The cutter 1s formed'with a depression or channelat one side, which is arranged to alford communication between thesevered ends of the two fuse columns, so that the flash from one column,when the severed portion has been con sumed, passes into the severed.end of the second column, which burns in the reverse direction, untilthe flash passage leadin to the magazine is reached, the shell being ten exploded.

A fuse of this kind can be completely mclosed so as to be protected-fromatmospheric action and we may arrange to inclose Specification ofLetters Iatent.

with the downward extension I) Patented Nov. 18, 1919.

Application filed November 11, 1918. Serial No. 262,055.

In order that the said invention may be clearly understood and readilycarried into effect, we will describe the same more fully with referenceto the accompanying drawings, in which Figure 1 is a longitudinalsection through a shell fuse constructed in accordance with thisinvention;

Figs. 2 and 3 are cross sections respectively on the lines oa w and y-yof Fig. 1;

Fig. 4 is a detail view showing the securing of the ends of the fusecolumns; and

Fig. 5 is an end view of a dome or chamber containing thefuse.

A is the fuse body carrying the central stem a and screwed at a in theend of the shell. B,"B are 'two columns of slowburning compositioninolosed in lead tubes and placedone above the other. The upper column Bterminates at one end in the cap 5 while oneend of the lower column ismade passing throughthe fuse body A and leading to the fuse magazine Cin the base of the body. The two columns B, B are shown of circularform. D is the time ring, in thevided with the overhanging lip h whichengages under the nose gof the knife G.

The knife G is adjustable by means of the time ring D through thegreater part of a circle between the lines zz (Figs. 2 and 3) indicatingrespectively the beginning and end of afuse column. The fuse compositionisv removed from the cap end of the upper tube B so as to provide forzero timing, the, flash from the cap igniting the fuse compositionatabout the position indicated by the upper line a. The ends of the tubeB, B

' are clampedin placeby the blocks 5 and ire the screws 6 securing theblocks to the fuse body A. The knife G is pivoted at g? on the end ofthe'bracket g and is formed; atf o'n e side with the recess ordepression g 'which', when the knife is operated to cut the two tubes orcolumns B, B, provides for dire t communication between the upper andlower tubes at the point ofsection', so that when the portion of thecompositioninthe-up er tube which is adjacent to the cap I) as burnt outthe flame is led directly to-the' cor responding position to the secondorlower tube B? and the flame passes backward tlirough 'the reversecolumn of composition until it reaches the tube extension 6- of thelower tubewhen the flame ignites'the-maga zine C and the shell is fired.

The inertia member H is of disk form with a central conical boss 78arranged to strike and fire the det'onating cap I) of the upper fusetube only at-about the end of'the movement of the knife G560 thatignition of the fuse cannot take place until the tubes have beenplaced-in communication with'one another. This is arrangedfor by theproportions of the inertia member H- and the form' of the knife,the nose9" of which lies in the recess formed by the'flange h and'lip' h" of theinertia member, the lip securely holding" the knife in inoperative.position until the set back of the inertia member drives the knifebackwardr-the'lip h bearing upon the curved back 9 0f the knife.

The inertia member H is normally held in position by the'saddle springZfi placed inside the plug ring 7L screwed in the upper end of themember H, the device beingheld in position on the stema by meansof thecap F, which isscrewed upon the outer reduced end a of thestem and isfixed in position by a cross pin or other locking'device.

On firing the shell the set back ofth'e member H' bends down thesaddlespring h andthe' member is' then free to operate the knife'G',driving the latter back so as to sever the fuse tubes B, B and placethem in communication' through the recess g of the knife,whereupon'the"conical boss k of the member H strikes thefuse cap Z) and ignites theinitial end of the'fuse composition which thereupon burns at thepredetermined rate until the portion of the'column which has beensevered by the knife has been consumed. The knife itself prevents the"flame reaching'the continuation of the firstcoliunn but directs itthrough the recess or de res sion 9 into the severed e'n'd ofth'e:second colunmBQ which burns in the-reverse"directlbli to Its" end, thetime o'f'burnin'g' being" reduced according to the roportion of thetubes which has been cut out of action the knife; As the angularadjustment of the" knifei s effected by, the-time ring D, which'isfreeto-tunr around thetubes-Bi; B-"1'ying 'foro freely in the grooves(Z, the effective length of the fuse columns can be adjusted from zeroposition up to a maximum indicated bythe'second or lower line z.

The dome E forms a complete inclosure for the fuse and is made toprovide substanti al internal volume so as to keep the conditions duringthe burning of the fuse compo sition as constant as possible and toavoid the development of high pressures. It is very desirable toprotect'the'f'use fronr atmospheric action' until the shell isfired andfor this purpose-the dome E forms a complete' andair tight inclosureopened automatically to the atmosphere on firin the shellfrom the gun.This is; eflected by the set back acting upon small lead or other plugse placed inconical or outwardly expanding apertures e in the end of thedome imn'iediat'ely below the cap F. The cap F extends at itslip fslightly beyond the'dome surface and an annularchannel f is formedin'sidethe lip" which, as shown in Fig. 1, extends overthe outer part ofthe plugs e, the under surface'of-the cap inside the channel projectingover the inner edges of the plugs so as to'prevent any danger of theiraccidentally coming out of the conical or e):- panded apertures,

WVhen the shell is fired from the gun the setback of the lead orotherplugs is suflicient to cause them to force their way inwardlythrough theapertures e and to open the" interior of the dome to the atmospherethro'ughthe channel f ofthe cap. The passage of the shell through theair at high velocity causes considerable suction behind the lip ofthecap'and consequently a substantial reduction of pressure is producedin'sidethedome, so that the air and the gases generated" by the burningfuse composition are withdrawn; This reduction in pressure reduces therate of burning of the fuse and improves the constancy of conditionsexisting during b'urningi so that not only is a greater time obtainedfor a given length of com osition" but the timing'of" the fuse'can beeffected with greater accuracy owing to the continuous withdraw'al ofthe products of combustion as they are formed.

What I- claim and desire to secure by Letters Patent of the UnitedStates is 1 In" a time fuse for" shells,- a protected colunnrofhlse'compositiom a relatively adjustable cutter; means fo'roperating thecutter'by the set back on firing the shell from a gun, seas tosever't'he colui'nn' of composition; a" fuse magazine and means-forafi'o'rd ing': operative communication between the severed endofthee-011mm and the ma azine.

2 In a time fuse for she-11s; a protected column of fuse compositionbent into" a curve;-anangnlarly adjustable cutter, means crating thecutter to' sever the column by th'e'set"backdueto firing the-shell froma gun, a fuse magazine and means for affording operative communicationbetween the severed end of the column and the magazine.

3. In a time fuse for shells, two protected columns of fuse composition,a relatively adjustable cutter adapted to sever the columns and at thesame time to provide communication between the severed portions of thetwo columns, and means for operating the cutter by the set back due tofiring the shell from a gun.

4. In a time fuse for shells, a protected column of fuse composition, arelatively adjustable cutter and an inertia member engaging with thecutter and positively holding it in inoperative position until the shellis fired from the gun, when the set back of the inertia member drivesthe cutter back ward to sever the fuse column.

5. In a time fuse for shells, two protected columns of fuse materialbent in superposed circles, a relatively adjustable cutter adapted tosever the columns and to provide communication between the severed endsof the columns, and means for operating the cutter by the set back dueto firing the shell from a gun.

6. In a time fuse for shells, a pair of curved columns of fuse material,lying side by side, and a cutter adapted to be operated by the set back011 firing the shell from a gun, which cutter is provided with adepression in its face forming a communication between the severed endsof the two columns.

7. In a time fuse for shells, a protected column of fuse composition, anadjustable pivoted cutter formed at the back with a projecting nose, andan inertia member of flanged disk form, which engages the nose to holdthe cutter normally in inoperative position, the said inertia member, bythe set back on firing the shell from a gun, driving the knife backwardto cut the fuse column.

8. In a time fuse for shells, a protected column of fuse compositionhaving a percussion cap at one end, a relatively adjustable cutter, andan inertia member adapted to hold the cutter normally in inoperativeposition and to drive it backward to cut the said column by the set back011 firing the shell from a gun, a part of the inertia member strikingthe cap to ignite the column when the latter has been severed by thecutter.

9. In a time fuse for shells, a pair of superposed circular columns .ofprotected fuse composition, a rotatable time ring having channels inwhich the said columns lie, a

pivoted cutter mounted u on the said time ring, and an inertia mem erengaging the said cutter and adapted to hold it normally in inoperativeposition, and to drive it backward to sever the columns by the set backon firing the shell from a gun.

10. In a time fuse for shells, a fuse body having a central stem, a pairof protected columns of fuse composition, a rotatable time ring havingchannels in which the said columns lie, a percussion cap at one end ofone of the columns, an extension at the corre sponding end of the secondcolumn leading through the fuse body to the fuse magazine, a cuttercarried by the time ring, an inertia member mounted to slide upon thecentral stem of the fuse bod and means for holding the inertia mem er inposition on the stem until the shell is fired from a gun, when the setback frees the inertia member and causes it to operate the cutter, whichsevers the columns of fuse composition.

11. In a time fuse for shells,a chamber normally closed to theatmosphere and containing the fuse, and means by which the chamber isopened to the atmosphere by the set back on firing the shell from a gun.

12. In a time fuse for shells, a normally closed chamber containing thefuse and hav ing an aperture leading to the atmosphere, and a plug ofsoft material closinc the said aperture but adapted to open it by theset back on firing the shell from a gun.

13. In a time fuse for shells, a chamber containing the fuse andnormally closed to the atmosphere, means by which the said chamber maybe opened to the atmosphere by the set back on firing the shell from agun, and means by which the flight of the shell causes suction in theinterior of the chamber and discharges the gases into the atmosphere.

In testimony whereof I aflix my signature.

FREDERICK GEOFFREY LEES JOHNSON.

